Measles Vaccination Q&A

Background
Since January 2019, approximately 700 cases of measles have been confirmed in 22 states, with large outbreaks in New York and Washington. This is the greatest number of cases reported in the U.S. since 1994. In the decade before the live measles vaccine was licensed in 1963, an average of 549,000 measles cases, 48,000 hospitalizations, 1000 cases of chronic disability from acute encephalitis and 495 deaths were reported annually in the U.S.

Why have there been more measles cases in the U.S. this year?
The increased number of cases has been attributed to:
  • measles outbreaks in countries to which Americans travel, and therefore more measles cases coming into the U.S., and/or
  • more spread of measles in U.S. communities with pockets of unvaccinated people.
Who Should Get the MMR Vaccine and How Many Doses Should They Get?Children
Children should get two doses of MMR vaccine, starting with the first dose at 12 to 15 months of age, and the second dose at 4 to 6 years of age.
Adults who do not have evidence of immunity should get at least one dose of MMR vaccine.
Some Adults who do not have evidence of immunity should get two doses of MMR vaccine (separated by at least 28 days):
  • College students and students at post-high school educational institutions.
  • Healthcare Workers.
  • People with HIV Infection who are >12 months of age and who do not have evidence of severe immunosuppression.
  • Household members and close contacts of immunocompromised persons.
International Travelers
Before any international travel:
  • Infants 6 to 11 months of age should receive one dose of MMR vaccine. Infants who get one dose of MMR vaccine before their first birthday should get two more doses (one dose at 12 through 15 months of age and another dose separated by at least 28 days).
  • Children > 12 months of age should receive two doses of MMR vaccine, separated by at least 28 days.
  • Teenagers and adults who do not have evidence of immunity against measlesshould get two doses of MMR vaccine separated by at least 28 days.
Women of Childbearing Age 
  • Women of childbearing age should make sure they are immune to measles before they get pregnant. Women of childbearing age who are not pregnant and do not have evidence of immunity should get at least one dose of MMR vaccine.
  • It is safe for breastfeeding women to receive MMR vaccination. The baby will not be affected by the vaccine through breast milk.
Who Does Not Need an MMR Vaccine?
A person is protected against measles and does not need an MMR vaccine if they meet any of these criteria for evidence of immunity:
  • Written documentation of adequate vaccination: o at least one dose of a MMR vaccine administered on or after the first birthday for preschool-age children and adults not at high risk for exposure and transmission o two doses of MMR vaccine for school-age children and adults at high risk for exposure and transmission, including college students, HCWs , international travelers, and groups at increased risk during outbreaks
  • Laboratory confirmation of measles at some point in their life. Laboratory confirmation of immunity to measles.
  • Born before 1957. (The majority of people born before 1957 are likely to have been infected naturally and therefore are presumed to be protected against measles. The exception is that HCWs born before 1957 should receive two doses of MMR vaccine).
If a person is unsure whether they’ve been vaccinated, they should first try to find their vaccination records. If they do not have written documentation of MMR vaccine, they should get vaccinated. The MMR vaccine is safe even if they are already immune tomeasles (or mumps or rubella).

Do people who got the killed measles vaccine in the 1960s need to be revaccinated with the current, live measles vaccine?
Yes, people who know they got the killed measles vaccine (an earlier formulation of measles vaccine that is no longer used) should get revaccinated with the current, live MMR vaccine. Not many people fall into this group; the killed vaccine was given to less than 1 million people between 1963 and 1968. If a person is unsure whether they fall into this group, they could ask their doctor to test their blood to determine whether they’re immune or they can just get a dose of MMR vaccine. There is no harm in getting another dose of MMR vaccine if they are already immune to measles (or mumps or rubella).
Who Should Not Receive the MMR Vaccine or Postpone Vaccination?
  • Persons who have any severe, life-threatening allergies to a previous dose or to a component of the vaccine.
  • Women who are pregnant. Pregnant women should wait to get MMR vaccine until after they are no longer pregnant. Women should avoid getting pregnant for at least one month after getting the MMR vaccine.
  • Persons who have a severely weakened immune system due to disease (such as cancer or HIV infection with evidence of severe immunosuppression) or medical treatments (such as radiation, immunotherapy, steroids, or chemotherapy).
  • Persons who have a parent, brother, or sister with a history of immune system problems should speak to their provider.
  • Persons who have a h/o thrombocytopenic purpura or thrombocytopenia.
  • Persons who have recently received a blood transfusion or other antibody containing blood products may be advised to postpone MMR vaccination for 3 months or more.
  • Persons who have gotten any other vaccines in the past 4 weeks. Live vaccines given too close together might not work as well.
  • Persons with moderate or severe acute illness.
Do people need a booster vaccine? No. People who received two doses of measlesvaccine as children according to the U.S. vaccination schedule are protected for life, and do not ever need a booster dose.
Do adults who only got one dose of measles vaccine as a child need a second dose? Most adults born after 1957 only need one dose of measles vaccine. Certain adults who are going to be in a setting that poses a high risk for measles transmission should get two doses separated by at least 28 days. These adults include:
  • students at college or other post-high school education institutions
  • HCWs
  • international travelers
  • people who public health authorities determine are at increased risk for getting measles during a measles outbreak
What should a person do if they are unsure whether they are immune to measles? The person should first try to find their vaccination records of measlesimmunity. If they do not have written documentation of measles immunity, they should either get vaccinated with MMR vaccine or have a doctor test their blood to determine whether they’re immune. There is no harm in getting another dose of MMR vaccine if they are already being immune to measles (or mumps or rubella).
How effective is the measles vaccine? The measles vaccine is very effective. Two doses of measles vaccine are about 97% effective at preventing measles if exposed to the virus. One dose is about 93% effective. About 3 out of 100 people who get two doses of MMR vaccine will get measles if exposed to the virus. However, they are more likely to have a milder illness, and are less likely to spread the disease to other people
How long does it take for the measles vaccine to work in your body? Detectable antibodies generally appear within just a few days after vaccination. People are usually fully protected after about 2 or 3 weeks. People traveling internationally should make sure to be fully vaccinated at least 2 weeks before you depart.
What should a person do if they’ve been exposed to someone who has measles?Promptly call their doctor and let them know that they have been exposed to someone who has measles. Their doctor can:
  • make special arrangements to evaluate them, if needed, without putting other patients and medical office staff at risk, and
  • determine if they are immune to measles based on their vaccination record, age, or laboratory evidence.
If a person is not immune to measles, MMR vaccine or a medicine called immune globulin may help reduce their risk developing measles. Their doctor can advise them, and monitor them for signs and symptoms of measles. If they are not immune and do not get MMR or immune globulin, they should stay away from settings where there are susceptible people (such as school, hospital, or childcare) until their doctor says it’s okay to return.

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